Systematic study of the pp to pp omega reaction

Abdel-Bary, M.; Wuestner, P.; Lehmann, A.; Jaekel, R.; Meyer, W.; Wenzel, R.; Clement, H.; Teufel, A.; Stinzing, F.; Naumann, L.; Wirth, S.; Georgi, J.; Gillitzer, A.; Kuhlmann, E.; Schoenmeier, P; Moeller, K.; Jaeger, H.; Dietrich, J.; Pinna, L.; Freiesleben, H.; Ritman, J.; Hesselbarth, D.; AbdEl-Samad, S.; Roderburg, E.; Ullrich, W.; Kress, J.; Zupranski, P.; Marcello, S.; Fanara, C.; Michel, P.; Sefzick, T.; Schulte-Wissermann, M.; Gast, W.; Filges, D.; Filippi, A.; Mauro, S.; Eyrich, W.; Sun, G.; Karsch, L.; Wagner, M.; Reimann, S.; Jakob, B.; Wagner, G. J.; Brinkmann, K.; Marwinski, S.; Kilian, K.; Koch, H.; Erhardt, A.; Moertel, H.; Schamlott, A.; Krapp, M.; Paul, N.; Steinke, M.; Gottwald, J.; Fritsch, M.; Wilms, A.; Pizzolotto, C.; Waechter, J.; Dorochkevitch, E.; Schroeder, W.; Morsch, H.P.; Wintz, P.; Dshemuchadse, S.; Plettner, C.; Richter, M.; Ehrhardt, K.

doi:10.1140/epja/i2010-10924-0

Journal Article

Systematic study of the pp to pp omega reaction

Abdel-Bary, M.FZJ* ; AbdEl-Samad, S.FZJ* ; Brinkmann, K. ; Clement, H. ; Dietrich, J. ; Dorochkevitch, E. ; Dshemuchadse, S. ; Ehrhardt, K. ; Erhardt, A. ; Eyrich, W. ; Fanara, C. ; Filges, D.FZJ* ; Filippi, A. ; Freiesleben, H. ; Fritsch, M. ; Gast, W.FZJ* ; Georgi, J. ; Gillitzer, A. ; Gottwald, J. ; Hesselbarth, D. ; Jaeger, H. ; Jakob, B. ; Jaekel, R.FZJ* ; Karsch, L. ; Kilian, K.FZJ* ; Koch, H. ; Krapp, M. ; Kress, J. ; Kuhlmann, E. ; Lehmann, A. ; Marcello, S. ; Marwinski, S.FZJ* ; Mauro, S. ; Meyer, W. ; Michel, P. ; Moeller, K. ; Moertel, H. ; Morsch, H. P. ; Naumann, L. ; Paul, N.FZJ* ; Pinna, L. ; Pizzolotto, C. ; Plettner, C. ; Reimann, S. ; Richter, M. ; Ritman, J.FZJ* ; Roderburg, E.FZJ* ; Schamlott, A. ; Schoenmeier, P. ; Schulte-Wissermann, M. ; Schroeder, W. ; Sefzick, T.FZJ* ; Steinke, M. ; Stinzing, F. ; Sun, G. ; Teufel, A. ; Ullrich, W. ; Waechter, J. ; Wagner, G. J. ; Wagner, M. ; Wenzel, R. ; Wilms, A. ; Wintz, P.FZJ* ; Wirth, S. ; Wuestner, P.FZJ* ; Zupranski, P.

2010
Springer Berlin

The European physical journal / A 44, 7 - 22 (2010) [10.1140/epja/i2010-10924-0]

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Please use a persistent id in citations: http://hdl.handle.net/2128/10325 doi:10.1140/epja/i2010-10924-0

Abstract: A systematic study of the production of omega-mesons in proton-proton collisions was carried out in a kinematically complete experiment at three excess energies (epsilon = 92, 128, 173MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Cooler Synchrotron COSY at Forschungszentrum Julich. The total cross-section, angular distributions of both omega-mesons and protons were measured and presented in various reference frames such as the overall CMS, helicity and Jackson frame. In addition, the orientation of the omega-spin and invariant-mass spectra were determined. We observe omega-production to take place dominantly in Ss and Sp final states at epsilon = 92, 128MeV and, additionally, in Sd at epsilon = 173MeV. No obvious indication of resonant omega-production via N*-resonances was found, as proton angular distributions are almost isotropic and invariant-mass spectra are compatible with phase space distributions. A dominant role of P-3(1) and S-1(0) initial partial waves for omega-production was concluded from the orientation of the decay plane of the omega-meson. Although the Jackson angle distributions in the omega p-Jackson frame are anisotropic we argue that this is not an indication of a resonance but rather a kinematical effect reflecting the anisotropy of the omega angular distribution. The helicity angle distribution in the omega p-helicity frame shows an anisotropy which probably reflects effects of the omega angular momenta in the final state; this observable may be, in addition to the orientation of the omega decay plane, the most sensitive one to judge the validity of theoretical descriptions of the production process.

Keyword(s): p p: interaction ; omega(783): hadroproduction ; total cross section: energy dependence ; p: angular distribution ; meson: production ; meson: spin ; meson: model ; COSY-TOF ; Juelich COSY PS ; p p --> p p omega(783)

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Note: The authors would like to express their gratitude to the COSY staff for the operation of the accelerator during these experiments. Fruitful discussions with C. Hanhart, W. Glockle, B. Kampfer, A. A. Sibirtsev, and A. I. Titov are gratefully acknowledged. This work was supported in part by grants from BMBF(DD117I) and COSY-FFE (Forschungszentrum Julich).; 17 pages, 16 figures, accepted for publication in EPJA

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